Ignore exit code zero from activated services

A variety of system components have migrated from legacy init into DBus
service activation.  Many of these system components "daemonize", which
involves forking.  The DBus activation system treated an exit as an
activation failure, assuming that the child process which grabbed the
DBus name didn't run first.

While we're in here, also differentiate in this code path between the
servicehelper (system) versus direct activation (session) paths.  In
the session activation path our error message mentioned a helper
process which was confusing, since none was involved.

Based on a patch and debugging research from Ray Strode <rstrode@redhat.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/test/name-test/test-activation-forking.py b/test/name-test/test-activation-forking.py
new file mode 100644
index 00000000..0d820754
--- /dev/null
+++ b/test/name-test/test-activation-forking.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+
+import os,sys
+
+try:
+    import gobject
+    import dbus
+    import dbus.mainloop.glib
+except:
+    print "Failed import, aborting test"
+    sys.exit(0)
+
+dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
+loop = gobject.MainLoop()
+
+exitcode = 0
+
+bus = dbus.SessionBus()
+bus_iface = dbus.Interface(bus.get_object('org.freedesktop.DBus', '/org/freedesktop/DBus'), 'org.freedesktop.DBus')
+
+o = bus.get_object('org.freedesktop.DBus.TestSuiteForkingEchoService', '/org/freedesktop/TestSuite')
+i = dbus.Interface(o, 'org.freedesktop.TestSuite')
+
+# Start it up
+reply = i.Echo("hello world")
+print "TestSuiteForkingEchoService initial reply OK"
+
+def ignore(*args, **kwargs):
+    pass
+
+# Now monitor for exits, when that happens, start it up again.
+# The goal here is to try to hit any race conditions in activation.
+counter = 0
+def on_forking_echo_owner_changed(name, old, new):
+    global counter
+    global o
+    global i
+    if counter > 10:
+        print "Activated 10 times OK, TestSuiteForkingEchoService pass"
+        loop.quit()
+        return
+    counter += 1
+    if new == '':
+        o = bus.get_object('org.freedesktop.DBus.TestSuiteForkingEchoService', '/org/freedesktop/TestSuite')
+        i = dbus.Interface(o, 'org.freedesktop.TestSuite')
+        i.Echo("counter %r" % counter)
+        i.Exit(reply_handler=ignore, error_handler=ignore)
+
+bus_iface.connect_to_signal('NameOwnerChanged', on_forking_echo_owner_changed, arg0='org.freedesktop.DBus.TestSuiteForkingEchoService')
+
+i.Exit(reply_handler=ignore, error_handler=ignore)
+
+def check_counter():
+    if counter == 0:
+        print "Failed to get NameOwnerChanged for TestSuiteForkingEchoService"
+        sys.exit(1)
+gobject.timeout_add(15000, check_counter)
+
+loop.run()
+sys.exit(0)